Ultrasonic endovascular catheter with a controllable sheath

ABSTRACT

A method for performing an endovascular procedure using ultrasonic energy includes providing a first sheath having a proximal end portion and a distal end portion, and having a first window in the distal end portion; positioning a wave guide in the first sheath for delivering the ultrasonic energy through the first window for performing the endovascular procedure; and selectively covering the first window with a cover.

TECHNICAL FIELD

This document relates generally to the art of endovascular proceduresand, more particularly, to an endovascular catheter using ultrasonicenergy to perform a medical procedure, such as an atherectomy orcrossing an occlusion, using a controllable sheath.

BACKGROUND

Ultrasonic catheters have been proposed. An example of such a catheteris shown in U.S. Pat. No. 7,540,852, the disclosure of which is fullyincorporated herein by reference. While this catheter achieves thedesired result of providing enhanced disruption of blood vesselobstructions, the present disclosure proposes certain modifications orimprovements to enhance the results achieved during an endovascularprocedure in terms of clearing an obstruction from a vessel (such as,for example, an atherectomy for removing atherosclerosis from a bloodvessel, or for crossing an occlusion).

SUMMARY

According to a first aspect of the disclosure, an apparatus forperforming an endovascular procedure using ultrasonic energy. Theapparatus comprises a catheter including a proximal end portion and adistal end portion having a first window, which may be elongated in alongitudinal direction of the catheter. A wave guide is provided fordelivering the ultrasonic energy for performing the endovascularprocedure. A cover is also provided for selectively covering the window.

In one embodiment, the distal end portion of the catheter includes anopening through which the wave guide may pass. The catheter may comprisea first sheath including the first window. The cover may comprise arotatable second sheath for covering the first window of the firstsheath. The second sheath may include a second window for aligning withthe first window, as well as an opening through which the wave guide maypass.

According to a further aspect of the disclosure, an apparatus forperforming an endovascular procedure is provided. The apparatus includesa source of ultrasonic energy, and a wave guide for delivering theultrasonic energy for performing the endovascular procedure. A catheteris provided for receiving the wave guide. The catheter includes a firstwindow for transmitting ultrasonic energy from the wave guide and anopening at a distal end through which the wave guide may pass.

In one embodiment, a cover is provided for selectively covering thefirst window, which may be elongated in a longitudinal direction of thecatheter. The catheter may comprise a first sheath including the window,and the cover may comprise a rotatable second sheath for covering thewindow of the first sheath. The second sheath may include a secondwindow for aligning with the window of the first sheath. The secondsheath may further include an opening through which the wave guide maypass.

Still a further aspect of the disclosure pertains to an apparatus forperforming an endovascular procedure using ultrasonic energy. Theapparatus comprises a wave guide for delivering the ultrasonic energyfor performing the endovascular procedure. A catheter is adapted forselectively blocking or transmitting the ultrasonic energy from the waveguide.

In one embodiment, the catheter comprises a first window for exposing aportion of the wave guide. A cover is also provided for covering thefirst window. The catheter may comprise a first sheath including thefirst window and a second sheath forming the cover. The second sheathmay also comprise a second window corresponding to the first window. Oneor both of the first and second sheaths may be rotatably mounted to thecatheter. A source connected to the catheter may supply ultrasonicenergy to the wave guide.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawing figures incorporated herein and forming a partof the specification, illustrate several aspects of the ultrasonicendovascular catheter with a controllable sheath and, together with thedescription, serve to explain certain principles thereof. In the drawingfigures:

FIG. 1 is a schematic view of a prior art catheter system including anultrasonic catheter;

FIG. 2 is a side view illustrating a general layout of a prior artcatheter;

FIG. 3 is a partially cross-sectional, partially cutaway view of acatheter including an ultrasonic wave guide;

FIG. 4 is a side view of a catheter with a controllable sheath accordingto one aspect of the disclosure;

FIG. 5 is a close-up view of the distal end portion of the catheter ofFIG. 4; and

FIGS. 6 and 7 illustrate an alternate embodiment.

Reference will now be made in detail to the presently disclosedembodiments of the inventive aspects of the ultrasonic endovascularcatheter with a controllable sheath, examples of which are illustratedin the accompanying drawing figures.

DETAILED DESCRIPTION

Ultrasound or ultrasonic catheters provide for disruption of occlusionsin blood vessels, such as for example, plaques, clots, lesions, or likeobjects that hinder blood flow. Catheters generally include a catheterbody (shaft), an ultrasonic energy transmission member disposed withinthe catheter body and a distal head coupled with the energy transmissionmember and disposed at or near the distal end of the catheter body. Theultrasonic wave guide transmits ultrasonic energy from an ultrasonictransducer to the distal end of the catheter, causing it to vibrate and,thus, disrupt, dissolve, or debulk vascular occlusions (which proceduresare generally called atherectomies or thrombectomies). A number ofimproved features of such an ultrasonic catheter are outlined more fullyin the following description.

Referring now to FIG. 1, one embodiment of an ultrasonic catheter system20 includes an ultrasound or ultrasonic catheter 10 and an energy source16 (which may comprise an ultrasonic generator). Catheter 10 includes adistal end 26 for disrupting occlusions, a catheter shaft or body 27,and a proximal connector 12 for coupling catheter 10 with an ultrasonictransducer 14. Ultrasonic transducer 14 is coupled with source 16 via aconnector 28, and generator is coupled with a control, such as afoot-actuated on/off switch 18 via another connector 29. Source 16provides energy to transducer 14 and, thus, to ultrasonic catheter 10.

Catheter 10 further includes an ultrasonic wave guide (or “corewire”—not shown in FIG. 1) that extends through the catheter body 27 andtransmits energy from the transducer 14 to the distal end 26. Someembodiments of catheter 10 include a guidewire, which in FIG. 1 is shownas a so-called “rapid exchange” guidewire 13 and guidewire port, whileother embodiments include a proximal guidewire port for over the wireguidewire delivery. In some embodiments, transducer 14 further includesa coupler 15 for coupling the catheter 10 to transducer 14. Connectors28, 29 may comprise an electric cord or cable or any other suitableconnecting devices for coupling on/off switch 18, source 16 andtransducer 14. In an alternative embodiment, on/off switch 18 is locatedon source 16.

In addition to proximal connector 12, ultrasonic catheter 10 may includeone or more other various components, such as a Y-connector 11 includinga fluid inlet port 17 (or aperture) for passage of irrigation fluid.Inlet port 17 may be removably coupled with an irrigation tube 24, whichin one embodiment may be coupled with a fluid refrigerator 30. Therefrigerator 30 may, in turn, be coupled with a fluid container 32 via aconnector tube 34. This arrangement may be used for introducing one ormore fluids into catheter 10. Fluid may be used to cool any part of thedevice, such as the ultrasonic wave guide, thus helping reduce wear andtear on the catheter 10. In some embodiments, fluid inlet port 17 islocated farther proximally on proximal connector 12, to allow fluid tobe applied within connector 12. In some embodiments, refrigerated fluidis used, while in other embodiments irrigation fluid may be kept at roomtemperature. In various embodiments, oxygen supersaturated fluid,lubricious fluid, or any other suitable fluid or combination of fluidsmay be used, and again, such fluids may be refrigerated or kept roomtemperature. In an alternative embodiment to that shown in FIG. 1,refrigerator 30 and fluid container 32 are combined in one unit.

Generally, catheter 10 may include any suitable number of side-arms orports for passage of a guidewire, application of suction, infusingand/or withdrawing irrigation fluid, dye and/or the like, or any othersuitable ports or connections. Also, ultrasonic catheters 10 per thedisclosure may be used with any suitable proximal devices, such as anysuitable ultrasonic transducer 14, energy source 16, coupling device(s)and/or the like. Therefore, the exemplary embodiment shown in FIG. 1 andany following descriptions of proximal apparatus or systems for use withultrasonic catheters 10 should not be interpreted to limit the scope ofthe appended claims.

Referring now to FIG. 2, an enlarged view of catheter 10 is shown.Proximal connector 12, Y-connector 11, inlet port 17, catheter body 27,distal end 26 and guidewire 13 are all shown. Catheter body 27 isgenerally a flexible, tubular, elongate member, having any suitablediameter and length for reaching a vascular occlusion for treatment. Inone embodiment, for example, catheter body 27 preferably has an outerdiameter of between about 0.5 mm and about 5.0 mm. In other embodiments,as in catheters intended for use in relatively small vessels, catheterbody 27 may have an outer diameter of between about 0.25 mm and about2.5 mm. Catheter body 27 may also have any suitable length. As discussedbriefly above, for example, some ultrasonic catheters have a length inthe range of about 150 cm. However, any other suitable length may beused without departing from the scope of the present disclosure.

Referring now to FIG. 3, a proximal portion of one embodiment of anultrasonic catheter 110 is shown in cross-section. An ultrasonic waveguide 140 extends from a sonic connector 152 distally to a distal end(not shown) of catheter 110. A catheter body 127 of catheter 110 isshown only in part in this Figure, whereas catheter body may extenddistally to (or near) the distal end of catheter 110, as shown in FIG.4, with the wave guide 140 also extending a particularly long distance(e.g., 30 centimeters or greater, and typically between about 15centimeters and 30 centimeters). The catheter body 127 may be a constantdiameter, or may have a variable diameter from the proximal to thedistal end (such as, for example, wider in diameter at the proximal endnear the point of entering the vasculature than at the distal end).

Catheter 110 also includes a proximal housing 112 (or “proximalconnector”), having an inner bore 144 (or “inner cavity”) in which sonicconnector 152, a portion of ultrasonic wave guide 140 and one or morevibration absorbers 150 reside. Housing 112 is coupled with aY-connector 111, which includes a fluid inlet port 117 (or aperture),and Y-connector 111 is coupled with catheter body 127.

In various embodiments, housing 112 may suitably include one or moresurface features 142 for increasing the overall surface area of theouter surface of housing 112. Increased surface area enhances theability of housing 112 to dissipate heat generated by ultrasonic waveguide 140 out of catheter 110. Surface features 142 may have anysuitable size or shape, such as ridges, jags, undulations, grooves orthe like, and any suitable number of surface features 142 may be used.Additionally, housing 112 may be made of one or more heat dissipatingmaterials, such as aluminum, stainless steel, any other conductivemetal(s), or any suitable non-metallic conductive material(s).

In most embodiments, ultrasonic wave guide 140, such as wire, extendslongitudinally through a lumen of catheter body 127 to transmitultrasonic energy from an ultrasonic transducer 14 (not shown in FIGS. 2and 3), connected to the proximal end of proximal housing 112, to thedistal end of catheter 110. Wave guide 140 may be formed of any materialcapable of effectively transmitting ultrasonic energy from theultrasonic transducer 14 to the distal end of catheter body 127,including but not limited to metals such as pure titanium or aluminum,titanium or aluminum alloys, or shape memory materials (such asnitinol), and may be coated (such as using a polymeric material). Again,additional details of ultrasonic wave guides 140 may be found in thepatent applications incorporated by reference. Similarly, reference maybe made to the incorporated references for descriptions of housing 112,sonic connector 152, vibration absorbers 150, Y-connector 111 and thelike. For example, housing 112 and other features are described in U.S.Pat. No. 7,335,180, the disclosure of which is incorporated herein byreference.

Ultrasonic wave guide 140 typically passes from a sonic connector 152,through bore 144 and Y-connector 111, and then through catheter body127. Fluid inlet port 117 is in fluid communication with a lumen inY-connector, which is in fluid communication with a lumen extendingthrough catheter body 127. Thus, fluid introduced into fluid inlet port117 is typically free to flow into and through catheter body 127 tocontact ultrasonic wave guide 140. Fluid may flow out of catheter body127 through apertures in the distal head (not shown) or through anyother suitable apertures or openings, such as apertures located incatheter body 127 itself. Any suitable fluid may be passed through fluidinlet port 117 and catheter body 127, such as refrigerated fluid,lubricious fluid, super-saturated saline or contrast/saline mixture, orthe like. Cooling and/or lubricating ultrasonic wave guide 140 mayreduce friction and/or wear and tear of ultrasonic wave guide 140, thusprolonging the useful life of ultrasonic catheter 110 and enhancing itsperformance.

Referring now to FIG. 4, it can be understood that the catheter body 127may take the form of a sheath 127 a in which the wave guide 140 is atleast partially positioned. The proximal end of the sheath 127 a may bepositioned adjacent to the housing 112, and may extend within theY-connector 111, as shown in FIG. 3, or may be external to it, as shownin FIG. 4. In either case, the sheath 127 a may be adapted to rotaterelative to the wave guide 140, as indicated by action arrow R.Alternatively, the sheath 127 a may be fixed in position relative to theconnector 111 or housing 112.

The sheath 127 a may also include a lateral or side opening, such as awindow 127 b, adjacent to a portion of the wave guide 140, and thusexposing it to the interior of a lumen or vessel when positionedtherein. As indicated in FIG. 5, the sheath 127 a may be rotatedrelative to the wave guide 140, such that the direction of theultrasonic energy is controlled by the position of the window 127 b(note action arrows E) or, alternatively, the entire catheter 110 may berotated if the sheath is fixed. In either case, by selectivelycontrolling the position of the window 127 b through rotation, a focusedor targeted treatment may be provided for a particular area of thevessel in which the catheter 110 is at least partially positioned, sinceonly a portion of the wave guide 140 is exposed to the opening thusformed.

To allow for an enhanced level of control, the window 127 b may also beselectively blocked. This may be achieved by providing a cover 128 forselectively covering the opening or window 127 b in the sheath 127 a. Asindicated in FIGS. 6 and 7, the cover 128 may comprise a second sheath128 a over the first sheath 127 a, such that the two structures aregenerally concentric about the wave guide 140. This second sheath 127 amay also extend to the proximal end of the catheter 110, such asadjacent to or within the connector 111, and may include an open end 128c. The second sheath 128 a may further include a lateral or sideopening, such as a window 128 b, which may have a size and shapematching or corresponding to window 127 b in the first sheath 127 a.

Thus, as indicated in FIG. 6, the second sheath 128 a may be rotatedrelative to the first sheath 127 a (which may be fixed or stationary, oralso rotatable as noted above) such that the window 127 b is covered bya portion of the second sheath. In this manner, the energy may bedirected to wave guide 140 through the open end 127 c of the sheaths 127a, 128 a, and the catheter 110 may be used in crossing a chronic totalocclusion (CTO) in this configuration.

When it is desired to allow for ultrasonic energy to be transmittedradially of the longitudinal axis of the catheter 110, the second sheath128 a may be rotated to align the windows 127 b, 128 b. This allows theenergy (arrow E) to pass into the vessel through the opening thusformed, as shown in FIG. 7. The relative rotation may also be achievedsuch that the opening only partially exposes the wave guide 140, whichmay provide for a further level of control.

Control of the relative rotation may be achieved at the proximal end ofthe catheter by providing suitable markings on the sheaths 127 a, 128 ato indicate the aligned position of the openings or windows 127 b, 128b. The markings may be in the form of printed indicia, but may also takethe form of bosses or embosses (and may be arranged to interact tocreate a temporary locked condition). Alternatively, radiographicvisualization may be used, such as by providing one or more radiopaquemarkers on the periphery of the windows 127 b, 128 b. Alignment of themarkers under fluoroscopy may indicate the aligned position of thewindows.

In summary, an improved ultrasonic catheter 110 includes a controllablesheath 127 a or 128 a. One or both of the sheaths 127 a, 128 a mayinclude windows 127 b, 128 b and may be adapted for relative rotation.By aligning the windows 127 b, 128 b to form an opening, thetransmission of energy from a wave guide 140 associated with thecatheter 110 may result. Yet, the catheter 110 may also be used in a“crossing” mode, such as for crossing a CTO, by reorienting the sheaths127 a, 128 a and thus closing the opening formed by the windows 127 b,128 b and regulating the transmission of ultrasonic energy.

The foregoing description has been presented for purposes ofillustration. It is not intended to be exhaustive or to limit theembodiments to the precise form disclosed. Obvious modifications andvariations are possible in light of the above teachings. For instance,instead of rotatable sheaths 127 a, 128 a, one or both of the sheathsmay be made to telescope relative to each other to selectively uncoveror block the opening for transmitting energy radially from the waveguide 140. The size and shape of the opening formed by the window 127 bor 128 b may also be altered from what is shown in the drawings to suita particular desire or need in terms of a treatment regimen. Allmodifications and variations are within the scope of the appended claimswhen interpreted in accordance with the breadth to which they arefairly, legally and equitably entitled.

1-20. (canceled)
 21. A method for performing an endovascular procedureusing ultrasonic energy, comprising: providing a first sheath having aproximal end portion and a distal end portion, and having a first windowin the distal end portion; positioning a wave guide in the first sheathfor delivering the ultrasonic energy through the first window forperforming the endovascular procedure; and selectively covering thefirst window with a cover.
 22. The method of claim 21, wherein thedistal end portion of the first sheath includes an opening through whichthe wave guide may pass.
 23. The method of claim 21, wherein the covercomprises a second sheath.
 24. The method of claim 23, comprisingrotating the second sheath to selectively cover the first window of thefirst sheath.
 25. The method of claim 23, comprising rotating the secondsheath to align a second window of the second sheath with the firstwindow of the first sheath.
 26. The method of claim 23, wherein thesecond sheath includes an opening through which the wave guide may pass.27. The method of claim 21, comprising aligning a second window of thecover with the first window of the first sheath.
 28. The method of claim21, wherein the first window is elongated in a longitudinal direction ofthe first sheath.
 29. The method of claim 21, wherein the cover is asecond sheath, the method comprising aligning a second window of thesecond sheath with the first window of the first sheath.
 30. The methodof claim 29, wherein the act of aligning is effected by rotating one ofthe first sheath and the second sheath relative to the other of thesecond sheath and the first sheath.
 31. A method for performing anendovascular procedure, comprising: providing a source of ultrasonicenergy; providing a wave guide for delivering the ultrasonic energy;providing a catheter for receiving the wave guide, the catheterincluding a first sheath having a first window to expose a portion ofthe wave guide; and moving a second sheath for selectively covering thefirst window of the first sheath.
 32. The method of claim 31, furthercomprising selectively aligning or misaligning the second window of thesecond sheath with the first window of the first sheath.
 33. The methodof claim 31, wherein the second sheath includes an opening through whichthe wave guide may pass.
 34. The method of claim 31, wherein the firstwindow is elongated in a longitudinal direction of the first sheath. 35.The method of claim 31, wherein the act of moving is effected byrotating one of the first sheath and the second sheath relative to theother of the second sheath and the first sheath.
 36. A method forperforming an endovascular procedure, comprising: providing a firstsheath having a first window for exposing a portion of a wave guide fordelivering ultrasonic energy through the first window for performing theendovascular procedure; and selectively covering at least a portion ofthe first window to vary an amount of ultrasonic energy that can beemitted through the first window.
 37. The method of claim 36, whereinthe act of selectively covering comprises moving a second sheathrelative to the first sheath to select an opening size of the firstwindow.
 38. The method of claim 36, wherein the act of selectivelycovering comprises moving a second window of a second sheath to at leastpartially cover the first window of the first sheath.
 39. The method ofclaim 36, wherein the act of selectively covering comprises rotating asecond sheath to selectively align or misalign a second window of thesecond sheath with the first window of the first sheath.
 40. The methodof claim 39, wherein the second window is rotationally misaligned withthe first window to at least partially cover the first window.